mumford



No. 6l7,l75. Patented Jan. 3; I899. J. A. MUMFURD.

TOWING MACHINE.

(Application filed June 28, 1898.)

(No Model.)

WITNESSES //V VENTOI? A TSTOHNEY.

mz NORRIS PEYZRS co. FNOTO-LITHOY. WASHINGTON, D. c

arn *1 tries,

JOSEPH A. MUMFORD, OF IIANTS PQRT, CANADA.

TOWING-MACHINE.

SPEGIFIOATI ON forming part of Letters Patent N 0. 617,175, dated January 3, 1899,

Application filed June 2 8, 1898.

To all whom it may concern:

Be it known that I, JOSEPH A. MUMFonD, a citizen of the Dominion of Canada, residing at Han tsport, in the Province of Nova Scotia, in the Dominion of Canada, have invented new and useful Improvements in Towing-Machines, of which the following is a specification.

My invention relates to a steam or air pressure towing-machine which is provided with means for protecting the towing hawser against breaking or injurious strain caused by variation of and excessive stress, particularly when the force of the engine of such machines is automatically controlled and regulated by a back-pressure valve in the exhaust-pipe of the engine, as shown in my invent-ion, for which my application for Letters Patent was placed on file May 20, 1898, the serial number of which is 681,204.

The nature of my invention, as shown in the following specification, consists of the peculiar simple means I employ for establishing in such towing-machines a positive automatic connection between such said valve and the said engine to secure a perfect reciprocity of action between them, whereby the force of the engine that holds the stress of the towing-hawser is made to vary to balance the varying resistance of the tow by automatically controlling and operating the action of the back-pressure valve in its exhaustpipe. This I accomplish by the mechanism illustrated in the accompanying drawings, in which Figure 1 represents a longitudinal elevation showing my device and only such other parts of the towing-machine as will clearly show the relation of my device thereto, and Fig. 2 a transverse elevation showing an end view.

Similar numerals of designation refer to similar parts of both views.

1 represents the towing-hawser; 2, the winding-drum 3, Fig. 2, a friction-holder of the drum; 4, a spur-wheel attached to the drum; 5, the crankshaft on which is a pinion 6, that operates the said spur-wheel; 7, the crank-disks; 8, the cylinders of the engine 3 9, Fig. 1, a steam-chest of the engine; 10,

the exhaust-pipe of the engine; 11, a back- Serial No. 684,705. (No model.)

pressure valve on the exhaust-pipe 12, the spindle of the said valve elongated into a rod; 13, a stuffing-box on said spindle; 14, a rocker-arm keyed to the end of the said valve spindle or rod 15,a worm-sleeve on the crankshaft 5; 16, a sleeve which makes a part of the moving end of the rocker-arm 14, and 17 a rod that slides out and in the said sleeve 16 and is held in any position in the said sleeve by the nip-screw 18. The left-hand end of the said rod 17 works between the threads of the worm on the crank-shaft 5 when it (the rod) is set up.

The rod 17, that connects the rocker-arm 14 with the worm 15 on the crank-shaft 5, is somewhat less in diameter than the space between the threads of the said worm, the purpose of which will be hereinafter explained.

Having enumerated the several parts of my device, I will now explain the general operation of my invention.

WVhen the hawser is to be run off of the drum to take a towor is to be again wound on the drum when the tow is dropped off, the operation is performed by working the throttlevalve of the towing-machine engine in the ordinary manner of working such engines; but when a tow is taken on the throttle-Valve is placed wide open and the entire force of the engine applied to the hawser, which yields a greater power than is required, whereupon.

the back-pressure valve is set by hand that is, partially closed by manipulating the rocker-arm 14-thus diminishing the force of the engine (now under full' steam) until it balances the stress on the hawser with the tow in hand under ordinary conditions of sea, weather, and draft. This being done, the rocker-arm 14 is now put in connection with the worm 15 on the crank-shaft 5 simply by crowding the rod 17 between the threads of the said worm and holding it there by the nipbolt 18. If now the hawser is by whatever cause submitted to extra stress, it will begin to pay out and rotate the worm 15, whereby it will begin to open wider the back-pressure valve 11 in the exhaust-pipe 10, which will cause the engine to yield more force to bal ance the extra stress on the hawser, and when the extra tension on the hawser is removed the extra force now of the engine will begin to draw in and recoil the hawser, whereby the back-pressure valve in the exhaust-pipe will begin to be closed, which will correspondingly diminish the force of the engine, and this will go on until the force of the engine again balances the tension of the hawser under the steady ordinary stress.

To give the engine a slight margin of motion both in paying out and drawing in the cable under variable tensions and so to render the varying force of the engine gentle and easy on the hawser, I make the locking-bar 17 somewhat less in diameter than the space be- .tween the threads of the worm 15, in which it works, which allows the worm to make part of a revolution before it begins to act on the back-pressure valve, which is a very desirable feature of my device. Thus it'will be seen that by this simple and convenient means, including only the back pressure valve, the worm, and rocker-arm, (having the connecting and disconnecting pin 17,) the force of the engine is automatically controlled and made to adjust its force to meet and balance any variation of stress of the hawser to which it may be submitted by whatever condition of sea or weather, and when the tow is not on the automatic device can be wholly detached from the engine by simply drawing back the rod 17, leaving the engine free to be employed for coiling and uncoiling the hawser or doing any other needed work.

I will here state that I have shown some of the features of the device herein described in my application above alluded to; but in that application this device was shown as a modification, and I could not claim it in connection with the other claims I desired to make in that application.

WVhat I now claim, and desire to secure by Letters Patent, is

1. In a steam or air pressure towing-machine, the combination of a back-pressure valve in the exhaust-pipe having on the spindle thereof a rocker-arm, the movable end of which is connected with one of the shafts of the engine having thereon a worm which engages with and operates the said rocker-arm, as and forthe purpose set forth.

2. In a steam or air pressure towing-machine, a back-pressure valve in the exhaustpipe thereof in combination with a rockerarm having an attachable and detachable connection with a worm on one of the shafts of the said machine as and for the purpose de* scribed.

JOSEPH A. MUMFORD. lVitnesses:

' C. H. JAooBUs,

E. II. GOURLEY. 

